To really support Entra in particular, you must have to reference Entra's implicit spec, which is roughly documented here:

https://github.com/AzureAD/SCIMReferenceCode/tree/master/Mic...

One way this comes up is that the way those C# objects serialize, there are properties that Microsoft will send you in form `"key": { "value": "xxx" }`, but which they expect that you read back to them of the form `"key": "xxx"`.

It's best to not take the SCIM RFCs too literally.